The invention relates to screening devices, and in particular screening devices suitable for ballast cleaning and of the kind which are mounted on track travelling frames and which are utilized to separate the fines from the ballast stones of fouled ballast by means of screens and which redistribute the ballast stones on the track. In known devices of this kind problems have been encountered because of the nature and configuration of the screen, which only utilizes the weight of the fouled ballast to knock the dirt fines through the screen.
It is the object of the present invention to provide a screening device which subjects both the fines and ballast to sufficient force to separate and remove the dirt from the ballast.